Also add clang-format-all.sh and clang-format-separate.sh to perform this operation.

These files sit in the ./src directory.

Bug: b/144825072
Change-Id: I5228ac59f7781ad1307c305949af7e7f9e0c31d1
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/24308Tested-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>